1 files changed, 38 insertions, 0 deletions
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 23db562cde07..ded707a50af8 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1288,6 +1288,44 @@ release:
 
 }
 
+vm_fault_t do_huge_pmd_device_private(struct vm_fault *vmf)
+{
+	struct vm_area_struct *vma = vmf->vma;
+	vm_fault_t ret = 0;
+	spinlock_t *ptl;
+	swp_entry_t swp_entry;
+	struct page *page;
+	struct folio *folio;
+
+	if (vmf->flags & FAULT_FLAG_VMA_LOCK) {
+		vma_end_read(vma);
+		return VM_FAULT_RETRY;
+	}
+
+	ptl = pmd_lock(vma->vm_mm, vmf->pmd);
+	if (unlikely(!pmd_same(*vmf->pmd, vmf->orig_pmd))) {
+		spin_unlock(ptl);
+		return 0;
+	}
+
+	swp_entry = pmd_to_swp_entry(vmf->orig_pmd);
+	page = pfn_swap_entry_to_page(swp_entry);
+	folio = page_folio(page);
+	vmf->page = page;
+	vmf->pte = NULL;
+	if (folio_trylock(folio)) {
+		folio_get(folio);
+		spin_unlock(ptl);
+		ret = page_pgmap(page)->ops->migrate_to_ram(vmf);
+		folio_unlock(folio);
+		folio_put(folio);
+	} else {
+		spin_unlock(ptl);
+	}
+
+	return ret;
+}
+
 /*
  * always: directly stall for all thp allocations
  * defer: wake kswapd and fail if not immediately available